1. Field of the Invention
The subject invention relates to tape winding methods and apparatus, such as peripheral drive tape transports, including systems for winding or transporting magnetic recording tape and other web-like materials.
2. Prior-Art Statement
Peripheral drive tape winding methods and apparatus are well known as such. For instance, U.S. Pat. No. 3,370,803 discloses a so-called Newell tape transport wherein a central drive capstan is in continuous peripheral engagement with supply and takeup rolls located on flangeless hubs and biased toward the capstan. The subsequent U.S. Pat. No. 3,482,800 discloses a further development of the Newell system wherein resilient idlers or compensating rollers are employed between the central capstan and each of the two tape rolls or packs. A specially constructed capstan for peripheral drive tape transports is apparent from U.S. Pat. No. 3,547,372.
A flanged reel peripheral drive system is shown in U.S. Pat. No. 3,130,975 wherein a capstan is alternatively applied to either of two driving disks which, in turn, engage and peripherally drive rolls of tape in a magazine-type recording machine.
A special type of peripheral drive system is disclosed in U.S. Pat. Nos. 3,528,625 and 3,583,618. This system bearing the assignee's trademark ASTRODRIVE has been extensively described by Irving Karsh in the article ASTRODRIVE--A NEW POWER-CONSERVING TAPE DRIVE, in the Proceedings of the International Telemetering Conference 1973, pp. 80 to 85. By way of generic expression, the phrase "peripheral drive capstan means" is herein employed to cover not only systems in which the capstan or a drive disk itself peripherally engages the tape roll, but to encompass at least also transports that employ an idler roller or other intermediary between the drive disk or capstan and the tape roll, as shown, for example, in some of the above mentioned prior-art references.
In practice, the peripheral drive capstan means are provided with a tire or outer sleeve of elastic material where they contact first the reel hub and then the tape wound on the particular hub. By way of example, such sleeve may be made of rubber or an elastomer. Apart from providing requisite friction, the elastic sleeve may have other operational functions as apparent from the apparent ASTRODRIVE article and patents.
While the mentioned elastic sleeve is not only advantageous but practically indispensable in most peripheral drive tape winding systems, it also has a severe drawback. In particular, during extended rest periods of the tape transport, the elastic sleeve on the peripheral drive capstan means is deformed by its contact with the hub that is biased relative to the capstan means. In other words, the elastic sleeve of the capstan means take a "set" which manifests itself in eccentric operation, imperfectly wound tape packs, deterioration of recorded and reproduced signals, and other disturbances.
No constructive solutions for this problem appear to be offered by the prior art, as may be seen from the above mentioned references, as well as from the disclosure of U.S. Pat. Nos. 2,913,192, 2,990,092, 3,093,284, 3,282,486 and 3,375,962, which are cited herein as a result of a novelty search not so much for any pertinancy, but rather for the sake of completeness.